Contemporary computing devices allow users to input information in a number of ways, including by keyboard, by one or more types of pointing devices, and by dedicated hardware buttons (typically on portable devices). Voice data and eye movement data (e.g., gaze detection) are other types of data users can input into computer systems via microphones and cameras, respectively.
With respect to pointing devices, a computer system may receive user input from a mouse and/or a touchpad, and if configured with a digitizer, by sensing stylus (pen) proximity and touch, e.g., entered via a pen or a finger. Some personal computers, such as tablet-based personal computers, have the digitizer built into the display screen. This is highly beneficial for many users, as such a computing device can be operated with or without a keyboard.
However, each input device has unique physical and ergonomic characteristics that result in various challenges. One important set of challenges arises because of the way various input devices interact with the content displayed on the screen. For example, a lot of user interface mechanisms such as drop down menus, scroll bars and so forth were modeled for interaction via a mouse, which is typically placed on the desk next to a computer monitor. However, a pen is used directly on the display itself. Thus, when using the pen, a user's hand often blocks a portion of the screen, making it difficult to interact with the computer. As one example, many dropdown menus are very difficult for right-handed users to use with a pen because they drop down so as to be obscured by the user's right hand. Scroll bars can be difficult to manipulate for left-handed users. In sum, these problems, as well as many other similar and related problems, are experienced by computer users as a result of the variety of alternative input devices.